Soil drainage is the frequency and duration of periods when the soil is free of saturation or partial saturation.The depth of occurrence and intensity of gley features usually indicate the drainage status/class of the soil.

Particle-size class is used to characterize the grain-size composition of the whole soil, including both the fine earth and the rock and pararock fragments up to the size of a pedon, but it excludes organic matter and salt more soluble than gypsum within